Christmas Eve, 1870. Richard Wagner and his wife, Cosima, had agreed not to give each other Christmas presents. They were simply too poor. But Wagner was planning a surprise gift.

For more than two months he had been crafting a piece of music to be performed outside Cosima’s bedroom door on Christmas morning. He had based it on themes later to be used in his opera Siegfried, plus a little nursery song he had written for their children two years earlier. He completed the Siegfried Idyll three weeks before Christmas and arranged for conductor Hans Richter to recruit the members of the small orchestra. Richter conducted secret rehearsals, first in Zurich then at a hotel in Lucerne.

Wagner invited philosopher Friedrich Nietzsche to the final rehearsal on Christmas Eve at the Hotel du Lac and they arrived together at the Wagners’ home in the village of Trihschen. There they found Cosima decorating the Christmas tree and preparing presents for the children.

At seven o’clock on Christmas morning the musicians arrived and quietly arranged themselves on the stairs outside Cosima’s room. They began to play.

“As I awoke to the light of dawn,” Cosima said later, “my mind passed from one dream into another. Familiar sounds from Siegfried came to my ears. It was as if the house—or more accurately—our entire being, was rising up in music and going up to heaven. Sacred memories, birdsong and sunrise, interwoven with music from Siegfried, soothed my heart and I came to realize that I was not dreaming, and yet was experiencing the most sublime of all dreams. Now at last I understood all of Richard's writing in secret.”

And yet Wagner had kept his pledge not to buy his wife a Christmas present. December 25th was Cosima’s birthday.